I built a gem for my own usage and when I want to install it I get the following:
$ gem install mygem
Successfully installed mygem-0.0.1
1 gem installed
Installing RDoc documentation for mygem-0.0.1...
Invalid output formatter
For help on options, try 'rdoc --help'
The gem works fine, but I would like to know what is causing this since I never saw it when installing any other gem. Looks like it is somehow related to RDoc but I couldn't find anything searching about it.
Thanks in advance.